Additive manufacturing processes sequentially bond materials together in order to form the completed part. Creation of the part is computer controlled and produces the part according to three-dimensional representations of the desired part or other part creation instructions. Material, also known as “feedstock,” may be bonded together via fusing layers or other small portions of material together.
Many current additive manufacturing techniques produce parts of limited size. The size of the part produced is constrained by the build volume of the additive manufacturing device. The build volume is the area in which the additive manufacturing device may create a part. A build volume is often defined in an XY plane by the area in which the additive manufacturing device may deposit or otherwise bond feedstock in forming the desired part. For example, in fused deposition modeling devices, the XY plane is defined by the lateral movement in the XY plane of the extruder which creates layers of the desired part. The initial layer is deposited onto a build platform or tray and subsequent layers are attached. The build volume is limited in the Z-direction by the maximum relative distance achievable between the build platform and the extruder or other bonding device. In some additive manufacturing devices, the build platform is connected to a z-axis step motor and moves as the part is created. In other devices, the extruder moves in the z-axis in addition to the x- and y-axes.
The size of the build volume is an inherent limitation of current additive manufacturing devices. Because this is a given volume, a continuous part can never grow larger than the build volume of a given machine. This poses a severely limiting problem where no object can be produced larger than the machine that is creating it. Today's additive manufacturing machines are growing print volume size in order to accommodate larger parts, but still there is an inevitable size limit on these machines. For instance, no additive manufacturing machine could be conceivably large enough to build an entire sky-scraper within its build volume; the machine would be far too large.
The size constraint placed on all additive manufacturing machines is a bottleneck. It severely limits the possible objects that could be built without any post machining to create the final part or structure.
Processes, such as those described in U.S. patent application Ser. No. 14/020,658 to Douglas, A., et al., have been created which produce large parts by dividing the desired part design into subparts which may be produced via additive manufacturing devices having limited build volumes. Connection features are added to each subpart design, enabling subparts to be connected together after production.
Given the foregoing, additive manufacturing devices which produce large, continuous parts without providing a build volume larger than the part itself are needed.